Dr. Terri Young is a pediatric ophthalmologist and Assistant Professor of Ophthalmology at the University of Minnesota. This award will enhance the candidate's potential for success by providing support for investigations into the molecular genetics of exaggerate eye growth, or myopia. Myopia, or nearsightedness is a refractive condition of the eyes with high incidence in the United States and one of the leading causes of blindness. Severe myopia predisposes the eye to glaucoma, macular degeneration, and retinal detachment. Genetic and environmental influences have been implicated, but specific factors responsible for myopia in humans have not bee identified. Several studies support the hypothesis that heredity is a major factor. In order to better understand the molecular genetics of myopia, we propose to characterize potential genetic factors of myopia through family studies with genome screening and linkage analysis. The overall goal of this proposal is to map genes responsible for familial severe myopia. Currently, 51 families have been recruited with an autosomal dominant pattern of inheritance of severe myopia (refractive error less than or equal to -6.00 diopters). Highly informative short tandem repeat polymorphisms have been utilized to confirm linkage and subsequently narrow the chromosomal region of interest. Significant linkage (Lod score= 6.24) has been identified at a locus on chromosome 18 in 8 families. Recently, significant linkage has been identified at a second locus on chromosome 12 (Lod score = 3.01) in one large multigeneration family. These potential candidate regions for myopia, as well as others that may be identified with the genome screen will be examined for mutations. This project is important to further our understanding of the molecular genetics of myopia, and may be generalized to enhance out understanding of the mechanisms of eye growth, whether normal, diminished, or excessive. Dr. Young's career goal is to flourish as a clinical scientist, with an established independent laboratory program in ophthalmic genetics. Dr. Richard king, the proposed sponsor, has extensive experience in the genetic analysis of complex diseases. The co-sponsors in this proposal will provide expertise in molecular genetics, ophthalmic genetics, and statistical analysis and epidemiology. With the support of the Mentored Clinical Scientist Development Award, the candidate will obtain a solid foundation in molecular genetics.